Basting stitch device in a zigzag sewing machine



United States Patent BASTING STITCH DEVICE IN A ZIGZAG SEWING MACHINE 1 Claim, 7 Drawing Figs.

U.S.Cl 112/158, 1 12/228 Int. Cl D05b 3/02, D05b 57/14 [50] Field ofSearch 112/158, 231,73, 109, 1 l l, 159,228,232

[56] References Cited UNITED STATES PATENTS 3,447,497 6/1969 Rendahl 112/158 Primary Examiner- Richard .I. Scanlan, .lr

. Altorney-Wenderoth, Lind & Ponack ABSTRACT: A device for obtaining a basting stitch in a zigzag sewing machine, comprising an improved shuttle race cap having holes or recesses through which a needle passes, and a shuttle body having a hook for seizing the loop of the upper thread, and characterized by that there is provided at one edge of said holes or recesses a downwardly bent wall to be inserted between the needle and the hook of the shuttle body, said bent wall being adapted to act as a barrier for preventing said hook of the shuttle body from seizing the loop ofthe upper thread at the right-hand or left-hand needle position.

Patent ed No\ r. 10, 1970 FIG.

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FIG..6

TAKESHI 0ND AND TOSHIO SAWADA,

INVENTORS A'ITORNEKS BASTING STITCH DEVICE IN A ZIGZAG SEWING MACHINE The object of the present invention is to provide a new device adapted for basting stitch in a zigzag sewing machine,

which is simple in construction and wherein a desired basting FIG. I is a plan view of a shuttle race cap of the zigzag sew- I ing machine according to the present invention;

FIG. 2 is a front view of the shuttle race;

FIG. 3 shows a sectional view taken along line A,A of FIG. 2;

FIG. 4 is a sectional view taken along line B,B of FIG. 2 shown in an enlarged scale;

FIG. 5 is a sectional view taken along line A,A of FIG. 2, showing the relation between the upper thread and the hook of the shuttle body;

FIG. 6 is a plan view showing the blind stitch, and

FIG. 7 is a plan view showing the basting stitch obtained by the provision of the device according to this invention.

Referring to the drawing, FIG. 2, line 8 -8 indicates the needle position (left), and line A,A, indicates the needle position (right). Assuming that a conventional zigzag sewing machine having a conventional shuttle race back is operated with the needle alternately held in said needle positions A -A and B,-B it would be possible to obtain a usual zigzag stitch or a blind stitch having pitch a, as shown in FIG. 6. In contrast with the above, according to the present invention, the shuttle race cap 1 is specially designed, so that in either the needle position (right) A,-A or in the needle position (left) 8,43 the hook 7 of the shuttle body 6 can not seize the loop of the upper thread I, whereby it is possible to obtain a basting stitch having larger pitch [2, as shown in FIG. 7.

In FIG. 2, showing a front view of the shuttle race body,

there is a shuttle race cap 1 secured to a shuttle race 13 by means of set screws 2. The shuttle race cap 1 has a recess 3 for passing the needle 8 at the needle position (left), and a hole 4 for passing the needle at the needle position (right), as shown in FIG. 1. One edge of the needle hole 4 is provided with a depending wall or projection 5 which is formed by downwardly bending at right angle an extension of the sheet metal forming the shuttle race cap 1. This bent portion or projection 5 is adapted to act as a barrier partition wall between the hook 7 of the shuttle body 6 and the needle 8 at the right-hand needle position, A A By the provision of said barrier partition wall 5, the hook 7 of the shuttle body is prevented from taking up the loop 9 formed by the upper thread t at the right-hand needle position, whereby the desired number of stitches may be skipped, and a desired basting stitch having pitch b is obtained when the needle stitches in the left-hand needle position. In FIG, 5, there is illustrated the manner of service of the barrier partition wall 5, in which the hook 7 of the shuttle body is prevented from seizing the loop of the upper thread I. On the otherhand, in FIG. 4 there is shown the relation between the hook 7 of the shuttle body 6 and the loop of the upper thread I at the left-hand needle position B -B where the loop 10 of the upper thread is taken up by the hook 7 of the shuttle body, resulting in the forming of a normal stitch. In FIG. 4, II designates the throat plate, and 12 is a cloth being sewed.

While in the embodiment of this invention described and illustrated in the drawing the bent wall 5 serving as a barrier partition wall is provided at the right-hand needle position A -A may be provided with respect to the left-hand recess 3 of the shuttle race cap I.

As shown in FIG. 2, the shuttle race I3 is held in position by means of clamps I4 and 15 pivoted on pivots 16 of a shuttle race cover 17. The shuttle I3 is detachable in an axial direction by oscillating the clamps 14 and 15 outwardly around the pivots 16. Thus, when it is desired, it is ossible to exchange t e shuttle race 13 having the cap designed specifically according to the present invention with an ordinary shuttle race without such specific cap.

From the foregoing it will be seen according to the present invention that a thin wall 5 may be inserted between the upper thread and the shuttle body hook at either the right-hand needle position or at the left-hand needle position to prevent the hook of the shuttle body from seizing the loop of the upper thread, whereby a desired number of stitches are skipped, so that the basting stitch, i.e., a straight stitch having a larger pitch may be obtained. Thus, the desired basting stitch may be readily obtained without requiring any special skill of the operator. Since it is possible to achieve the above mentioned advantage merely by providing the thin barrier wall between the needle and the hook of the shuttle body, the present invention is not subject to breakdown and other maintenance problems. Moreover, the specific structure of the new device according to this invention is very simple and would not be expensive.

We claim:

I. In a zigzag sewing machine having a vertically reciprocating sewing needle, a detachable shuttle race, and a shuttle body rotatably mounted in said shuttle race and having a hook for seizing a loop of upper thread from said needle, a basting device comprising a shuttle race cap secured to said shuttle race, said shuttle race cap having a hole and a recess therein through which said sewing needle passes, and a projection extending downwardly from said shuttle race cap atsaid hole between said hook of said shuttle body and said sewing needle, said projection serving as a barrier for preventing said shuttle body hook from seizing said loop of upper thread when said needle passes through said hole. 

